Conventionally, when a transfusion is performed to a patient, for example, a catheter assembly is used. This kind of catheter assembly can include a hollow catheter, a catheter hub adhered to a base end of the catheter, an inner needle inserted into the catheter and having a sharp needlepoint at a leading end, and a needle hub adhered to a base end of the inner needle. In a case where a transfusion is performed to a patient by using the catheter assembly, the catheter with the inner needle punctures a blood vessel of the patient, and the inner needle is evulsed from the catheter while the catheter is puncturing the patient after the puncture. Next, a connector provided at an end portion of a transfusion tube is coupled to a base end of the catheter hub, and a transfusion material is supplied into the blood vessel of the patient through the transfusion tube, the catheter hub, and the catheter.
It is known that a unit for supporting the inner needle through the catheter is provided in the above catheter assembly in order to inhibit or prevent deflection of the inner needle upon the puncture (for example, refer to JP 10-503094 W and US 2011/0282285 A).
JP 10-503094 W discloses that openable and closeable two arms extending in a leading end direction are provided on a needle hub, and the two arms are open before use and do not support an inner needle. A user pinches the arms upon a puncture so that the puncture can be performed while deflection of the inner needle is being inhibited. After the puncture, the user weakens the pinching force with respect to the two arms so that the two arms open and a catheter hub can move forward.
US 2011/0282285 A discloses that openable and closeable two arms extending in a leading end direction are provided on a needle hub, and, before use, the two arms have been closed, support an inner needle through a catheter, and have been restrained in a closed state by a restraining portion. In use, when the restraining portion moves forward, the restraint of the restraining portion is released. After that, when the two arms open in an upper and lower direction, a catheter hub becomes movable forward. The two arms have been coupled to each other at a base end portion of a catheter assembly through a hinge portion.
The catheter assembly described in JP 10-503094 W requires an operation in which the user strengthens and weakens the pinching force with respect to the two arms in order to perform support with respect to the inner needle and release from the support. Thus, the operation is complicated.
In the catheter assembly described in US 2011/0282285 A, since the two arms for supporting the inner needle open in the upper and lower direction, a protruding length of the inner needle from the arms is made long in order to avoid interference with skin of the patient. Thus, the inner needle easily deflects. Upon a puncture, the vicinity of leading ends of the arms in order to easily perform the puncture is held. After the restraint with respect to the arms has been released, it can be necessary to hold the vicinity of base portions of the arms (a base end portion of the catheter assembly) instead of the vicinity of leading ends of the arms in order to open the arms. Thus, the operation can be complicated.